Electromagnetic pickup for a stringed musical instrument

ABSTRACT

A device for sensing the vibrations of a stringed, musical instrument which includes an electromagnet having a diaphragm carrying a needle. The electromagnet being supported on the instrument isolated vibrationwise from the instrument body with the outer end of the needle engageable with the instrument bridge so that the device senses and amplifies the vibrations of the bridge during the playing of the instrument.

1,900,489 3/l933 Eisenbergus United States. Pat ent lnventor Joe D. Ellis g 1850 Christian Road, Charleston, S.C. 29407 1 Appl. No. 855,484 Filed Sept. 5, 1969 Patented Aug. 17, 1971 ELECTROMAGNETIC PICKUP FOR A STRINGED MUSICAL INSTRUMENT '5 Claims, 4 Drawing Figs.

[1.8. CI.... 84/l.l5 Int. Cl; Gl0h 3/00 Field of Search 84/115,- 1.16;, l.l 4, 294, 295, 296 7 References Cited I UNITED STATES PATENTS 2920,55? 11/1935 Loar... 84/294 3,192,304 6/ 1965 Rizzutti 84/1 1 5 3,236,930 2/1966 Fender 84/1. 1 5 3,244,791 7 4/1966 Hull 84/].16

. FOREIGN PATENTS 73 l,34l 9/1932 France 84/l.l 5

Primary Examiner-Milton O. Hirshfield Assistant Examiner-R. Skudy Attorney-T. Russell Foster ABSTRACT: A device for sensing the vibrations of a stringed, musical instrument which includes an electromagnet having a diaphragm carrying a needle. The electromagnet being supported on the instrument isolated vibrationwise from the instrument body with the outer end of the needle engageable with the instrument bridge so that the device senses and amplifies the vibrations of the bridge during the playing of the instrument.

I although; performssatisfactory; the quality of the musical sounds produced with the use, of such apickupis lessthan that J ELECT ROMAGNETIC PICKUP FOR A STRINGED MUSICAL INSTRUMENT.

' Many-devices are in use today forassociation ,with musical instruments to amplify the musical sounds produced by the instrument as it played; Such present-day' devices are generally of the electric-type-fontranslating the mechanical vibrations produced by the instrument into electrical impulses which are arnplified and 'fed into a suitableloud speaker system. One such device,.which is of the electromagnetic type,

I isshown in US. Pat. No. 486,264 issued-to ,l-larry De Armond'ahd entitled Violin.Microphone'fi The device-of this patent utilizes a floating diaphragm of thin ",magnetic material. which engages the body. of the instrumentsoasto sense the body'.vibrations when the instrument'is'played and translate these mechanical vibrations intoelectrical impulsesQThe device of this patent isparticularly adapted; for use onqa stringed musical .instrument and, in particular, a violin and desired particularlywherea large sound'amp'lit'lcation factor is employed such as would be required during the playing of the instrument inenclosures which are acoustically poor and/or in the presence of a high levelof background noise. a

"Efforts are continually being made to improve the purity a'ndtidelity of amplified musical sounds from a stringed'mu'sical-instrument by the use of devices whichrnore faithfully sensethe mech'anical vibrations of the instrument with only limited successklt has been recognized that one of the most sensitive parts of astringejd musical instrument which more faithfullyfollowsthe vibrations of the strings is the bridge'on which'the strings are supported but efforts'to. sense the bridge vibration utilizing electrical' picku ps have fallenlshort of the desired. result; particularly as far as the violinis concerned, whose musical notes', 'particularly. when they are amplified, are accompanied by pleasant sensations by an audience only when such notes are-virtually completely free of distortion. Accordingly, a primary object of this invention is to provide a new and novel electromagnetic'picku'p for a stringed musical instrument. I v I 7 h Another objectofthis'invention is.to.prov ide a new-and novel electromagneticpickupfor a'stringed musical instruj ment which permits the amplificationof the'musical'notes produced; on the instrume'ntto afr'elati 'ely high' level-with'a fidelity and purity of sound thatis virtually distortion free.

IA further object ofthisinvention is to; provide anew and novel electromagneticpickup.for a stringed musical instrument such as a violin which responds only .to the vibrations of the violin bridge as the violin-'is'played and permits the amplification of these vibrations over a wide range and including virtually all of the frequencies which the human ear can detect without interference in a distortion-free manner into sound highly pleasing to the ear. I v Still'another object of the invention is to provide afnew and ncvelelectromagnetic pickup which is capable of producing I pickup of FIG. 3.

.having atop wall and a sidewall, the ed'g'eportion of which defines an openinginwhichis disposeda floating diaphragm of magnetic material. A variable rheostat having an adjusting knob. and an electromagnet are positionedxinthe casing with the electromagnet,adjacent-the'diaphragrn"iand a cover of 7 rubber material is detachablymounted on the casing to retain the diaphragm in the casing opening. The=cover is-provided with an opening for exposing (a portiongvjof the diaphragm to which the inner end of'an-elongated-feelemis'secured with the feeler extending through the opening-outwardly from the easing and terminating in an 'outerend; Meansare provided for vadjustably supporting the pickup in suspended position on a claims. The invention itself, however, both'as to its organization and methodof operation maybe best understood by reference to the following description taken in conjunction with theaccompanying drawings. FlGQ '1 is a perspective view of a portion of a stringed musical instrument and in particular a violin tog: ther with the pickup of the invention in an operative positioni FlG. 2 is an enlarged view' of a portion of the pickup of FIG. 1 asiview'ed from below; I I F1613 is a side elevation view partially in section of the pickup of FIG. I in the operative position; and, v

F165 4' is an enlarged sectional view of a portion of the iReferring. now'to the drawing andto FlG. 1 in particular,

there is shown an-ele'ctrornagn'etic' pickup constructed in acsuch as a guitar, viola, etc.

cordance with the. invention and designated generallyby the letter'l. The pickup P is shown mounted in an operative posi tion on a stringed musical in'strument'such as a'violin, only a therefore theportion'shown being 'represe nta tively designated by the letter V. It should be" understood that although the pickup of the invention is particularly adaptable for use on a violin, it is also suitable for use on other 'st'ringedinstruments The violin Vwith the'jinvention is utili zedmaybe of conventional' construction including a body 11 shown partially in FIG. 1 having an upper surface 1m, a tailpiece l2 and a pmrality of strings IJ-attachedtd violin neck'(not shown) and the improved quality of sound corresponding directlyto anirm provernent in the quality of the musical instrument with which thepickup is utilized.

This invention further contemplates the provisionof a new andnovel electromagnetic pickup for a violinwhich is low in initial cost, which is of lightweight,v compact construction,

tailpiece 12 in the conventional-manner as shown and extending' over and in supported relationship with a bridge 14, As is.

well known, the bridge 14 is, suitably mountedon theupper surface [In of the body 11 and is formed from suitable material such as wood,.plastic or the like in a conventional configu ration asshown in FIG. 1. I i

The pickup P-of the invention incorporates many of the component parts of the electromagnetic pickup in the aforementioned patent, the differences in construction between the patented pickup and that of applicants by means of which the novel results of applicant's invention are obtained being expickupl includes a casing designated generally by the letter C 'plained in detail hereinafter. 'As shown best in FIGS. 1, 4, the

which is of substantially oblong-shape having an interior l5 and whichis provided witha top wall 16 and a continuous sidewall 17 having amarginal edge portion 18 defining an openiriglil in the bottom of the casing C. Preferably, the marginal edge portion 18' is flared outwardly slightly along its lower edge at 180, asshown best in- FIG. 4. The flared portion 18a is provided with a relatively thin coating 21 of resilient in- The objects of this invention and other related objects are accomplished by providing a pickup which includes a casing includes an adjusting knob 28 for varying the' amplification of sulatirig-materialsuchas rubber'by. dip coating or purpose to be explained hereinafter.

As shownin ,the aforementioned patent, an electromagnet the like for a 22whi'ch includes a coil 23 and a core 24 is positioned within .the interior 15 of the casing C. A variable rheostat designated generally bythe numeral 27 issupported on the casing C and impulthe pickup P,- the construction ofthe variable rheostat27 being similar to that shown and described'in the aforementioned patent. a

Circuit means are providedon the casing C for electrically connecting the electromagnet 22 and rhe'ostat 27 to an associated source of electrical power (not shown). The circuit means include a multiconductor power cord 31 which extends through thecasing sidewall 17 as shown best in FIG. 1 the conductors of the cord 31 being connectedto the rheostat 27 and the electromagnet 22 in a conventional manner as shown in'the aforementioned patent. As is well known, the power cord 31 is connected to an amplifier and loud speaker system,

n'eitherof these components being shown for clarity,'as

well as to the associated source of electrical power.

,' "A-diaphragm 32 of thin magnetic material, preferably metal. is" positioned in the casingopening 29, the diaphragm 32 being of substantially oblong shape to conform generally to the shape of the opening 19. As shown best in FlG 3, the marginal edge of the diaphragm 32 overlies the rubber coated marginal flange Ila of the casing sidewall 17 in engagement with the rubber coating 2! so as to insulate the diaphragm 32 from'the' metal of the crosscasing C. i -l l the bracket 56 in thefadjusted position. 1.. in the operation of the pickupof the invention, the 56 is positioned generally as shown in FIG. 1 with the pin 53 on the arm 52 extending through the bracket slot 58. The casing C is 'positionedso that the feeler end 426 is adjacent to the bridge and the thumbscrew 54 is preferably threadedly engaged withthepin '53 up to a'pos'ition such that free movement of the bracket 56 is permitted. The casing C is then moved forwardly of the violin V so that the feeler end 42b engages andpenetrates to a limited extent the material of the bridge 14 centrally intermediate the vertical side edges of the bridge and adjacent the bottom edge of, the bridge as shown,

the slot 58 being moved relative-to the pin 53 to accommodate this movernent. The thumbscrew sit is then tightened down A cover- 33 of resilient'insulating material'such as rubber having an, upstanding vmarginal flange .34 is detachably mountedon the marginal edge portion 18'. of -the casing sidewall 17 in surrounding relationship with :the marginal ilange- 18a and with the diaphragm 32.'Thus, the cover 33 retains the diaphragm in a floating position in the casing openingf19 sandwiched between the insulating material of the cover 33 and the rubber coating 21. in the preferredemb'odiment, the-diaphragm 32 is provided with the plurality of prongs or projections 36 which are punched from the metal of the diaphragm and which engage the rubber coating 2 I on the marginal flange Ila to center 'the'diaphragm in the proper position in the casing opening [9 adjacent the electromagnet 22 and prevent lateral movement of the diaphragm as shown best mFlG. 3.

Asi

hown best in FIG. 2, the cover 33 includes thickened portion 37 formed integrally therewith and a circularopening 38 i'oi' externally exposing a portion 3 2a of the diaphragm 32.

The'pickup P of the invention also incjlud'es an elongated teeler 41 which is preferably of circular cross-sectional shape and which has an outer end 42 and an inner and, preferably L-shaped as shown, secured by soldering'ortheiike centrally to the diaphragm portion 32:; so as to extend outwardly from the "casing C through the cover opening 38. The feeler 41, which in the illustrated embodiment is needle" shapedj and formed fronifinetal, is tapered towards its outer end 42, a portion 424 being preferably bent asshown a'ngularly relative to the remaining portion of the feeler 41 and terminating at a point 42b, for engagement with the bridge! as shown in FIG. 1

violin V in an elevated, operative position above the body 2 upper surface lie in spaced-apart, isolated relationship with we body i with the feeler outer end 42 in engagement with the bridge l4. More specifically, an arm 5] of metalor'the' like is provided which is secured by suitable means such as screws 52 to the violin tailpiece l2 transversely of the violin V so that an end portion 51a of the arm projects laterally outward from the tailpiece 12 as showmAs is well known, the tailpiece 12 of the violin Y is isolated vibration wise from the violin body il by conventional resilient means so that body vibrations produced as the violin is played are not transmitted to the tailpiece. Therefore. the arm 5i and other casing supporting parts, as well as the casing C described in detail hereinafter are not subjected to the vibrations of the violin body. An upstand ing threaded pin 53 is provided on the arm portion 51a which Means are provided for supporting the casing C on the I into retaining engagement with the bracket 56 to releasably point 42b in secure the casing C in this position with the feeler penetrating engagement with the bridge 14,

The power cord 31, preferablyextending. through the chinrest'(not shown) of the violin V is connected to the associated source of power, amplifier and loudspeaker system in the conventional manner so that the violin V may now be played. As the violin V is played, the vibrationsv of the bridge 14 responding to the vibrations of the strings l3 aretransmitted through the feeler 41 to the diaphragm 32, these mechanical vibrations beingtranslatedin the 'well-knownmanner by the electromagnet 22 intoelectrical'impuises forthe reproduction of sound, the degree of amplification of the sound beingdetermined by manual adjustment of the knob 280i the variable rheos tat 27.

it can be seen that there has been provided with the novel arrangement 0f the invention an electromagnetic pickup by means of which musical notes of the highest purity and fidelity may be'produced from a stringed musical instrument and, in particular a violin, throughout wide range of amplification and virtually. free of distortion, theseoutstanding results have been obtained by. utilizing in part a well-known electromagnetic pickup,,the construction of which has been modified to as to permit thesensing of-vib'rations of theviolin bridge'completely fre'e'ofvibrations from the violin body. in addition, not only is arranged for threaded engagement with a retaining member ship with the axis of the violin V and includes an end portion are notesof high quality produced from arel'atively inexpensive instrument regardless of the background noise level and regardles'sof the degree of amplification through the pickup of the invention, but whenthe pickup is used on a stringed instrument of higher quality, corresponding higher quality musical sounds are obtained, a result not' previously obtained with present day electromagnetic pickup devices.

Having thus described the invention, what i claim is:

I. An electromagnetic pickupfor a stringed muscial instrument of the type including a body, a tailpiece, a plurality of strings, and a bridge for supporting said strings in spacedrelationship withthe .uPP surface of said body, comprising, in combination, a casing having a top wall and a sidewall having a marginaledge detiningan opening in said casing, an electromagnet positioned in said eating, a variable rheostat having an adjusting knob supported on said casing, circuit meanson said casing for electrically connecting said electromagnet and said rheostat to an associated source of electrical power, a diaphragm of magnetic material positioned in said opening, a cover of resilient insulating material detachably mounted on said casing marginaledge portion for retaining said diaphragm in said casingopening, said cover having an opening for externally exposing a portion of said diaphragm, an elongated feeler member having an inner end secured to said diaphragm, said feeler member extending outwardly from said casing through said cover opening and having anoiiter end arranged for engagement with said bridge, means for supporting said engage and secure bracket casing on said instrument in an elevated, operative position over said body upper surface and in spaced-apart, isolated relationship with said body with said feeler member outer end in engagement with said bridge to permit the vibrations of said bridge to be translated into electrical impulses by said pickup for the reproduction of sound.

2. An electromagnetic pickup in' accordance with claim 1 wherein said feeler member comprises a tapered, needleshaped member of metallic material having a pointed outer end, said pointed outer end being arranged to penetrate said bridge to a limited extent in said operative position of said casmg.

3. An electromagnetic pickup in accordance with claim 2 including a coating of resilient insulating material on said marginal edge portion of said casing, said diaphragm having a marginal edge portion engageable with said coating in the retained position of said diaphragm in said casing opening to insulate said diaphragm from said casing.

4. An electromagnetic pickup inaccordance with claim 3 including a plurality of upstanding integrally formed prongs on said diaphragm marginal edge-portion, said prongs being arranged to engage said coating on said casing marginal edge portion to resist lateral movement of said diaphragm relative to said opening.

' 5. An electromagnetic pickup in accordance with claim 1 wherein said mounting means include an arm secured to said tailpiece in transverselyextending relationship with said in-.

strument and having an end portion extending laterally outward from said tailpiece, an upstanding pin mounted on said arm end portion, a bracket secured at one end to said casing and arranged to be positioned in longitudinally extending relationship with the axis of said instrument, said bracket having a slot adjacent its other end for accommodating said pin in a selected position relative to said slot for longitudinal adjustment of said bracket, a retaining member mounted on said pin extending through said bracket slot for engagement with said bracket to releasably retain said bracket in the selected, iongitudinally adjusted position for engagement of said bridge with said feeler member. 

1. An electromagnetic pickup for a stringed muscial instrument of the type including a body, a tailpiece, a plurality of strings, and a bridge for supporting said strings in spaced relationship with the upper surface of said body, comprising, in combination, a casing having a top wall and a sidewall having a marginal edge defining an opening in said casing, an electromagnet positioned in said casing, a variable rheostat having an adjusting knob supported on said casing, circuit means on said casing for electrically connecting said electromagnet and said rheostat to an associated source of electrical power, a diaphragm of magnetic material positioned in said opening, a cover of resilient insulating material detachably mounted on said casing marginal edge portion for retaining said diaphragm in said casing opening, said cover having an opening for externally exposing a portion of said diaphragm, an elongated feeler member having an inner end secured to said diaphragm, said feeler member extending outwardly from said casing through said cover opening and having an outer end arranged for engagement with said bridge, means for supporting said casing on said instrument in an elevated, operative position over said body upper surface and in spaced-apart, isolated relationship with said body with said feeler member outer end in engagement with said bridge to permit the vibrations of said bridge to be translated into electrical impulses by said pickup for the reproduction of sound.
 2. An electromagnetic pickup in accordance with claim 1 wherein said feeler member comprises a tapered, needle-shaped member of metallic material having a pointed outer end, said pointed outer end being arranged to penetrate said bridge to a limited extent in said operative position of said casing.
 3. An electromagnetic pickup in accordance with claim 2 including a coating of resilient insulating material on said marginal edge portion of said casing, said diaphragm having a marginal edge portion engageable with said coating in the retained position of said diaphragm in said casing opening to insulate said diaphragm from said casing.
 4. An electromagnetic pickup in accordance with claim 3 including a plurality of upstanding integrally formed prongs on said diaphragm marginal edge portion, said prongs being arranged to engage said coating on said casing marginal edge portion to resist lateral movement of said diaphragm relative to said opening.
 5. An electromagnetic pickup in accordance with claim 1 wherein said mounting means include an arm secured to said tailpiece in transversely extending relationship with said instrument and having an end portion extending laterally outward from said tailpiece, an upstanding pin mounted on said arm end portion, a bracket secured at one end to said casing and arranged to be positioned in longitudinally extending relationship with the axis of said instrument, said bracket having a slot adjacent its other end for accommodating said pin in a selected position relative to said slot for longitudinal adjustment of said bracket, a retaining mEmber mounted on said pin extending through said bracket slot for engagement with said bracket to releasably retain said bracket in the selected, longitudinally adjusted position for engagement of said bridge with said feeler member. 